Re: [gpsd-users] Raspberry Pi, GPIO PPS and NTP

[hans mayer]

sorry, forgot the attachments


Am 12.06.2016 19:59, schrieb hans mayer:
> dear Chris,
>
> but the reason is clear and logical.
> the 1PPS comes very exactly witch an interval of 1 second.
> the SHM information is generated out of the serial interface
> of the gps module. and this is far away to have a
> constant interval.
>
> i run a ntp server with a type 22 as clock source and
> type 28 as time information.
> and SHM driver floats around +- 10 ms while
> PPS is about +- 10 us ( micro seconds ) for offset
> see attached files.
> ( i didn't try SHM to bring to an average of 0 )
>
> and of course this reflects the jitter too.
>
>
> kind regards
> hans

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